1. Field of Invention:
This invention relates to masks or light shields adapted to cover a wearer's eyes to exclude ambient light and thereby promote slumber, and more particularly to a disposable, one-piece device of this type.
2. Status of Prior Art:
There was no need for light shields before the modern era, for then working and sleeping habits and the hours assigned thereto were dictated by the sun's trajectory, so that one generally worked during the day and slept at night. The concept of a night shift is of modern origin, for the strong artificial illumination necessary for this purpose represents a relatively recent advance. Also unthinkable before the modern era was air travel that traversed time zones at such high speeds as to foreshorten the night and make it necessary to sleep under daylight conditions.
Adequate sleep is essential to well being, for without sleep one is deprived of the regenerative process which then takes place. Yet the modern era has created an environment which is unnatural, for large segments of the population are required to work at night which nature has reserved for sleep, and to sleep during daylight hours intended for human activity. And travellers often have no choice but to sleep under daylight conditions.
The human sensory system is not shut down during sleep, but remains alert in a standby state to protect the sleeper. Thus a sleeper will be awakened by a loud noise; for even in deep sleep his ears are highly sensitive to sound. While the amount of ambient light impinging on the eyes is sharply reduced when the eyelids are closed, because of the eye's extreme sensitivity to light, the closed eyes remain responsive to ambient light. It is for this reason that most people find it difficult to take a siesta or to enjoy prolonged sleep under daylight conditions or when the lights in a bedroom are turned on.
Because sleep has restorative power, adequate sleep is particularly important to one who is recovering from an illness or a surgical procedure. Indeed, one therapeutic technique that is reputed to be highly beneficial is to induce prolonged sleep in a patient for a period far greater than the normal 7 or 8 hour span.
Yet in modern hospitals patients are often deprived of adequate sleep. The need to monitor around the clock a patient's temperature, pulse rate, blood pressure and other variables that reflect the patient's condition interferes with sleep, for the attending nurse in a ward occupied by several patients may find it necessary to turn on certain bed lights during night sleeping hours and thereby disturb the sleeping patients. Typically, with a post-operative patient, lights are kept on all night so as to afford immediate staff access to a patient in need, to the discomfort of the patient's roommates.
In order, therefore, to cope with these conditions and to provide means to exclude ambient light from a person's eyes to permit him to sleep soundly during the day or in other situations where the prevailing light is such as to frustrate sleep, various light shields have been developed which are formed of fabric materials and are now commercially available.
These light shields or masks are effective to the extent that they all function to block ambient light and are suitable for travel, at home, at the beach or wherever the conditions are such as to require light shielding. Yet they all suffer from certain practical drawbacks. These can best be appreciated in the context of a general hospital having hundreds, if not thousands, of patients occupying beds, or in a nursing home where similar conditions prevail.
The first hospital requirement is that the light shield be sterile and therefore not a source of infection. It is a simple matter to sterilize a fabric light shield. But once this shield is worn by a patient, it is no longer sterile and must be discarded and not reused. In order for it to be practical for a hospital to supply patients with disposable, sterile light shields, the cost per shield must be very low, which is not true of existing fabric light shields. And finally, it must be easy for the patient or for the nurse to attach the shield to the patient's head. Existing non-disposable light shields which include adjustable headbands must be adjusted to the head size of the wearer, and this represents a practical disadvantage.
The above practical requirements are not limited to hospitals, for should an airline or a hotel wish to supply passengers or guests with disposable, low cost, sterile light shields, existing fabric light shields do not satisfy these requirements.
With these requirements in mind, let us now consider a typical commercially-available light shield. This shield is made of satin or rayon facing sheets covering a padded core and provided with a fabric rim or frame which is also padded, the general shape of this shield being similar to that of one-piece plastic sunglasses.
In order to hold this shield or mask on the wearer's head, it is provided at either end with ribbons or elastic straps and a buckle or clasp of some sort so that the joined straps can be adjusted to the wearer's head size.
The cost of the fabrics which make up this shield and the sewing operations for assembling the shield are such as to make this shield fairly costly. And while it is possible to sterilize this fabric light shield so that when it is put on it is then in sterile condition, once used it ceases to be sterile. But a hospital or airline cannot afford to provide a patient or passenger, each time the need arises, with a fresh sterile mask if each mask costs a few dollars. Also, because these light shields are adjustable, under hospital or airline conditions, the shield may not be easy to put on so that it stays in place.